From 3aea5ab8a883559f9385b2b366f7cb66b5ea04ec Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Tue, 21 May 1991 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1991-05-21

---
 port/stfcall.c | 224 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 224 insertions(+)
 create mode 100644 port/stfcall.c

diff --git a/port/stfcall.c b/port/stfcall.c
new file mode 100644
index 0000000000000000000000000000000000000000..80e90d72e1a5a74d81b4dd14505d49cfe325c8f2
--- /dev/null
+++ b/port/stfcall.c
@@ -0,0 +1,224 @@
+#include	"u.h"
+#include	"lib.h"
+#include	"mem.h"
+#include	"dat.h"
+#include	"fns.h"
+#include	"errno.h"
+
+#include	"fcall.h"
+
+#define DPRINT 	if(fcalldebug)kprint
+
+int fcalldebug = 0;
+
+typedef struct Fcalld	Fcalld;
+
+struct Fcalld{
+	int	dev;		/* ref. for debug output */
+	int	state;
+	int	type;		/* of current message */
+	int	need;		/* bytes remaining in current message */
+	int	nhdr;		/* bytes of header treasured up in hdr */
+	uchar	hdr[16];
+};
+
+enum {
+	Startup, Startup1, Begin, Header, Data
+};
+
+/*
+ *  fcall stream module definition
+ */
+static void fcalliput(Queue*, Block*);
+static void fcalloput(Queue*, Block*);
+static void fcallopen(Queue*, Stream*);
+static void fcallclose(Queue*);
+static void fcallreset(void);
+Qinfo fcallinfo =
+{
+	fcalliput,
+	fcalloput,
+	fcallopen,
+	fcallclose,
+	"fcall",
+	fcallreset
+};
+
+static Block *	putmsg(Queue*, Block*, int);
+
+static uchar msglen[] = {
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  3,  3,  3,  3,  0, 67,  5,  3, 89, 13,  7,  5, 33, 13,
+	  6, 13, 38, 13, 15,  8, 16,  7,  5,  5,  5,  5,  5,121,121,  5,
+	 35, 13,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+	  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0
+};
+static void
+fcallreset(void)
+{}
+
+static void
+fcallopen(Queue *q, Stream *s)
+{
+	Fcalld *f;
+
+	DPRINT("fcallopen %d\n", s->dev);
+
+	q->ptr = allocb(sizeof(Fcalld));
+	f = (Fcalld *)((Block *)q->ptr)->base;
+	f->dev = s->dev;
+	f->state = Startup;
+	f->type = 0;
+	f->need = 0;
+	f->nhdr = 0;
+}
+
+static void
+fcallclose(Queue * q)
+{
+	Fcalld *f = (Fcalld *)((Block *)q->ptr)->base;
+
+	DPRINT("fcallstclose %d\n", f->dev);
+	freeb(q->ptr);
+	q->ptr = 0;
+}
+
+void
+fcalloput(Queue *q, Block *bp)
+{
+	PUTNEXT(q, bp);
+}
+
+
+static void
+fcalliput(Queue *q, Block *bp)
+{
+	Fcalld *f = (Fcalld *)((Block *)q->ptr)->base;
+	int len, n;
+
+	len = BLEN(bp);
+	DPRINT("fcalliput %d: blen=%d\n", f->dev, len);
+	if(bp->type != M_DATA){
+		DPRINT("fcalliput %d: type=%d\n", f->dev, bp->type);
+		PUTNEXT(q, bp);
+		return;
+	}
+	bp->flags &= ~S_DELIM;
+	if(len == 0){
+		freeb(bp);
+		return;
+	}
+	while(len > 0)switch(f->state){
+	case Startup:
+		if (len == 1 && bp->rptr[0] == 'O'){
+			DPRINT("fcalliput %d: O\n", f->dev);
+			PUTNEXT(q, bp);
+			f->state = Startup1;
+			return;
+		}
+		if(bp->rptr[0] == 'O' && bp->rptr[1] == 'K'){
+			DPRINT("fcalliput %d: OK\n", f->dev);
+			bp = putmsg(q, bp, 2);
+			len -= 2;
+		}
+		f->state = Begin;
+		break;
+
+	case Startup1:
+		if(bp->rptr[0] == 'K'){
+			DPRINT("fcalliput %d: K\n", f->dev);
+			bp = putmsg(q, bp, 1);
+			len -= 1;
+			f->state = Begin;
+			break;
+		}
+		f->type = 'O';
+		f->need = msglen['O']-1;
+		f->state = Data;
+		DPRINT("fcalliput %d: type=%d, need=%d\n",
+			f->dev, f->type, f->need);
+		break;
+
+	case Begin:
+		f->type = bp->rptr[0];
+		f->need = msglen[f->type];
+		f->nhdr = 0;
+		if(f->type == Twrite || f->type == Rread)
+			f->state = Header;
+		else
+			f->state = Data;
+		DPRINT("fcalliput %d: type=%d, need=%d\n",
+			f->dev, f->type, f->need);
+		break;
+
+	case Header:
+		n = f->need;
+		if(n > len)
+			n = len;
+		memmove(&f->hdr[f->nhdr], bp->rptr, n);
+		f->nhdr += n;
+		DPRINT("fcalliput %d: nhdr=%d\n",
+			f->dev, f->nhdr);
+		if(n == f->need){
+			f->need += f->hdr[f->nhdr-3];
+			f->need += f->hdr[f->nhdr-2] << 8;
+			f->state = Data;
+			DPRINT("fcalliput %d: need=%d\n",
+				f->dev, f->need);
+		}
+		/* fall through */
+
+	case Data:
+		if(f->need > len){
+			f->need -= len;
+			PUTNEXT(q, bp);
+			return;
+		}
+		bp = putmsg(q, bp, f->need);
+		len -= f->need;
+		f->state = Begin;
+		break;
+	}
+}
+
+static Block *
+putmsg(Queue *q, Block *bp, int n)
+{
+	Block *xbp;
+	int k;
+
+	DPRINT("putmsg: n=%d\n\n", n);
+	k = BLEN(bp) - n;
+	if(k == 0){
+		bp->flags |= S_DELIM;
+		PUTNEXT(q, bp);
+		return 0;
+	}
+	if(n <= k){
+		xbp = allocb(n);
+		memmove(xbp->wptr, bp->rptr, n);
+		xbp->wptr += n;
+		bp->rptr += n;
+		xbp->flags |= S_DELIM;
+		PUTNEXT(q, xbp);
+		return bp;
+	}
+	xbp = allocb(k);
+	memmove(xbp->wptr, bp->rptr+n, k);
+	xbp->wptr += k;
+	bp->wptr -= k;
+	bp->flags |= S_DELIM;
+	PUTNEXT(q, bp);
+	return xbp;
+}